The present invention relates to an articulating strut support strength member. More particularly, the field of this invention relates to a support member used inxe2x80x94but not limited toxe2x80x94the flexible coverings field with particular emphasis on marine canvas, vinyl and similar synthetic materials.
Additionally the field relates to an articulating knuckle insert compatible with industry standard marine grade structural tubing. Further, my field of invention relates to a knuckle insert which is shop fabricated for field installation within existing rigid support tubing as found, for example on boats, tents, temporary buildings and the like.
Explanation of Terms
Certain terms are used to introduce and explain the background of the art and the invention; and, for convenience and completeness sake, such terms are summarized in this section. These terms are not meant to supersede the claims nor the definition of terms as defined within the four corners of the specification; but, rather, are meant to further the understanding of the invention and briefly introduce the technical art stage for a detailed teaching of the improvement in the art as provided by this invention as claimed.
Locking Sleeve
A slidable tubular sleeve of an internal diameter a few thousands of an inch or so larger than the external diameter of its strut member counterparts. In most applications, such a sleeve has a mating configuration to the framework tubingxe2x80x94with such tubing often being cylindrical or box shaped in nature.
Latching Detents
Spring loaded balls which protrude partially through holes in each half, or sectional member, of a support strut. These detents retain the locking sleeve in place over an articulating bridge, thus locking the strut in an extended and taut position.
Articulating Bridge
A short, relieved and shaped, generally rectangular bridge which is hinge-pin connected at each end to identical, opposed image socket insert hubs. This articulating bridge, in concert with flat-faced mating socket hubs, create a double knuckle two axis, folding joint. An underneath section of this bridge is relieved sufficiently to provide rotation in excess of 90 degrees at each end. Such over 90 configuration provides additional freedoms of motion improving field installation flexibility in that outboard pivot point locations are less critical during field installations.
Insert (Sometimes Called Anchor Insert Hubs)
Relieved and shaped, but generally cylindrical, hubs of a snug fit diameter which are inserted into and fixed by pins to one member of a folding two member strut. Such hubs receive and house the ends of a bridge cross piece and provide folding capability for the joined strut sections.
On the folding part of my strut, these inserts are flat faced and when butted together one against the other act as load bearing surfaces for increased strut strength and rigidity.
Folding Strut
In mechanical terms, a strut is a brace fitted into a framework to add strength and rigidity. For this invention the term strut is generalized to include both structural halves or legs of a rigid tubing strength member. It further includes a center insert which includes a double knuckle geometry allowing the two halves of the strut to fold upon itself, in one direction, or unfold to a perfectly straight configuration.
Such a locked strut becomes a single rigid structural support member with improved compressive holding strength by virtue of a bridge and xe2x80x9cflat-facedxe2x80x9d inserts. That single strut member, in turn, often locks other struts or separate articulating framework members in place.
Axes of Rotation
Within the framework of this invention there are two axes of rotation within the double knuckle insert of the folding strut. In usage my folding strut cooperates with two additional axes of rotation at the outboard ends of the two strut halves. These outboard axes of rotation, or pivot points, are also the structural connecting points to a collapsible, skeletal framework. When a folding strut is extended and sleeve locked, both outboard axes of rotation become fixed by virtue of triangular geometry. The two axes within the double knuckle, and the outboard pivot points all rotate within the same plane.
Collapsible Covering
A generic term which includes bimini tops, dodgers, and other stretched coverings usually but not limited to weather exposed marine applications. A covering which by design is taut when fixed in place over a rigid framework, generally of cylindrical tubing construction.
Such a framework in marine applications is often pinned for a forward collapsing, articulating motion, and when opened, is held upward and rigid by straps in tension. This articulating framework is usually configured with one or more crossway structural bows which have been inserted through stitched sleeves in a canvas or vinyl covering.
Tension Strap
One or more generally downward and aft tending straps attached to the structural tubular framing of a Bimini Top, Dodger or Covering. With tension straps extended and secured, the covering is pulled taut and held upwardly in place to its maximum open and tautly stretched configuration.
Bimini Top
A canvas or synthetic covering stretched tautly over a skeletal framework. A temporary convertible covering usually positioned over an outside steering station on a powerboat or yacht.
Dodger
A weather covering of canvas like material stretched tautly over a curved, tubular framework on a dodger is temporary convertible covering over the forward portion of a sailboat cockpit and affording weather protection to both the steering station and the companionway entrance. Given the more limited deck space of a sailboat over a power yacht, dodgers are shaped and fitted to attempt optimization of weather protection and entrance/egress.
Articulating struts are well known and find many uses. Often such struts are manufactured in place as part of a customized larger equipment piece. Typical examples abound in the aircraft, space and marine and recreational industry. Often such struts employ many moving parts and are unusually complex for whatxe2x80x94on the surface or to a casual observerxe2x80x94is a seemingly simple and straightforward application. An aftermarket in these various technical disciplines exists, and such an aftermarket calls for pre-fabricated, field installation folding struts.
The marine recreation world, for example, broadly involves both sail and power boats. Such craft use canvas or synthetic fabric-covered apparatus extensively for protection from sun and rain. On power boats, these coverings are known generically as bimini tops and usually cover a substantial portion of a deck or outside steering station such as a flying bridge. Depending on weather usage preferences, these bimini tops are preferably folding and collapsible, usually in a forward direction, such that an operator may raise or lower the covering for personal preference and weather conditions.
In the sailboat world, similar but smaller coverings generically called dodgers, are used in much the same general fashion as the bimini tops on larger power boats. Sizes and shapes vary from boat to boat depending on specific boat deck designs which dictate attachment configurations.
Turning now to the prior art, a search has revealed various patents, several of which are only of peripheral relevance. Such patents include:
U.S. Pat. No. 4,580,829 to Metheopoulos (Apr. 8, 1986)
U.S. Pat. No. 4,819,300 to Jackson (Apr. 11, 1989)
U.S. Pat. No. 4,543,006 to Wang (Sep. 24, 1985)
U.S. Pat. No. 5,293,656 to Chan (Mar. 15, 1994)
U.S. Pat. No. 4,670,921 to Avni et al. (Jun. 9, 1987)
U.S. Pat. No. 5,745,954 to Shogan et al. (May 5, 1998)
U.S. Pat. No. 4,877,164 to Baucom (Oct. 31, 1989)
Each of these reference patents will be discussed briefly in order to point out the lack of significant relevance to this invention.
Matheopoulos has disclosed work in the field of vehicle visor hinging. Using cylindrical sleeved openings similar to a door hinge, Matheopoulos has detents to hold the hinged visor in one of several positions. Otherwise it is of no interest.
Matheopoulos lacks any teaching of a sliding shaft or spring loaded stop points, or longitudinally located hinge halves which fold upon themselves. Moreover, the hinge of the referencexe2x80x94positionallyxe2x80x94simply can not go from straight to folded upon itself and back again.
Jackson""s disclosure is disclosed for interior aircraft usage such as luggage compartments. Such a disclosure, with multiple moving parts, spring/pawl-reliance for locking and/or unlocking simply would not be cost effective for the marine uses of this invention.
The Jackson strut specifically is disclosed as an automatic spring loadedxe2x80x94not manualxe2x80x94lock. Moreover, the Jackson operation even demands a full fold to a pre-determined position before it can be automatically locked. Jackson is not bidirectional. Such a device is not applicable to the harsh conditions of the marine environment.
Wang""s disclosure is in the area of providing a folding multi-position ladder hinge, with an off center pinned hinge point in order to fold a ladder. His disks 11 and 21, that actually form the hinge flanges, are integral with the rods 12 and 22 to be folded. These hinge elements are not inserted into the rods to be folded.
Wang discloses a standard type hinge mechanism. The Wang stops and detent positioning devices are for radial positioning. Baucom is discussed with the Wang patent simply because they both compare with each other in several ways but are not comparable to the invention.
The Shogan et al and Chan patents are treated together since they are slight adaptations from one another.
Both references disclose hinge techniques in the field of folding baby crib or playpen support frames. By employing an external hinge housing, two rods may be foldedxe2x80x94but the rods do not internally house the hinge mechanism that provides a folding capability. The housings 20 and 40 of these prior art references do not move. Moreover, the hinging part of these references is a separate piece that is not, and could not, fit within the rods 21 of Chan or 22 of Shogan et al.
The Avni et al disclosure, in FIGS. 1, 2 and 11 shows a straight and folded-against-itself condition for rods 17 and 18. The Avni et al wedge 29 is spring loaded and locks the poles 17 and 18 in an extended or straight position. Other than this locking wedge, however, Avni et al has little relevance to the invention.
Here presentedxe2x80x94for the first timexe2x80x94is a new and improved strut having superior strength, flexibility in the field and a self supporting rigidity by use of offset hinge pins and exposed hub faces which serve several functions including acting as load bearing surfaces. A bi-directional, detent held, springless sleeve completes the structural rigidity equation, adds to the flexibility of my invention.
Briefly summarized, the folding strut of this invention includes a strong connecting link that is snugly fitted within a pair of opposed hubs, which hubs are themselves internally mounted in the ends of a pair of structural tubes or members. This two axis, pivoting link is seated in rounded cutout hub portions, and is pinned off-center, relative to the hubs. The hubs are fixed internally at the ends of a pair of opposed hollow cylindrical members, and have a face areas that are large and serve as an auxiliary load bearing surface.
Two spring-loaded detent push buttons positionally hold a slightly larger slidable sleeve in place when the tubes and sleeve are extended into a straight position. Manually depressing one or the other of the spring loaded detent buttonsxe2x80x94and, sliding the oversized sleeve from either direction toward the hinged centerxe2x80x94allows the strut (and thus the two tubes) to fold back upon itself.
My folding strut is readily installable into existing field tubing, and similar framework. My double knuckle is designed as a separate assembly with two identical, but opposed hub inserts having exposed load bearing faces. Such surfaces, when the strut is extended, bear against one another in compression providing increased strength and rigidity. Additionally, the two axis bridge and pin offset mechanically favors an extended configuration. Thus, such structure in combination with a bi-directional sliding locking sleeve provides a much, improved folding joint for a strut.
Further, I teach a method and apparatus for the creation and installation of a folding strut within an existing skeletal structure or framework. My novel invention mates with the same sizes and types of materials as those of typical marine coverings structures.
For example, in many marine applications, a bimini or canvas covering is provided for the outside steering station of power boat.
My hinge itself consists of two insert hubs with rounded slots milled in the opposed hubs. These slots house a central connecting bridge that has mated rounded ends pinned at offset locations such that the rounded ends of the link pivot within the hub slots as the outer strut members fold against themselves.
The internally located double knuckle allows each tube strut member to fold 90 degrees from its normal straight in-line position to a parallel side-by-side location when the strut is in a folded configuration. The hinge pins holding my bridge are offset from the strut""s longitudinal axis for the improved features presented herein.
It is an object of the invention to a provide an efficient strut which may be locked with a minimum of parts.
It is an object of the invention to provide a bi-directional sliding locking sleeve over a bridged insert pair.
It is an object to provide two spring and ball detents which may be inserted independently of other strut structural elements.
It is an object of the invention to provide a pre-fabricated, field installation articulating knuckle within a length of tubing.
It is an object to provide a two point knuckle which has a freedom of motion in one plane of zero degrees when fully extended up to 180 degrees when fully folded.
It is an object of the invention to use a material for a double knuckle that is lightweight, yet structurally strong and machineable.
It is an object of this invention to provide a replacement strut assembly should a strut be damaged in use.
It is an object to provide a rigid member between two covering bows, both of which may be rotationally pinned at one end.
It is an object to provide a centrally positioned articulating knuckle which cooperates with two outboard pivot points.
It is an object to provide a knuckle with two pivot points which are constrained to articulate in only one plane.
It is an object of the invention to provide an attachment method so that two outboard ends can be rotationally attached to marine hardware.
It is an object of this invention to allow collapsing and folding without removal of canvas.
It is an object to provide a knuckle and locking sleeve which is field installation into an existing framework for a marine covering.
It is a object of the invention to provide at least a pair of horizontal, folding struts between two tubular rotatable bows.
It is an object to provide a rigid, free standing, structural framework.